Spray cooling of the roofs of metallurgical vessels hag been practiced successfully as disclosed in U.S. Pat. No. 4,715,042--Heggart et al; U.S. Pat. No. 4,815,096--W. H. Burwell; and U.S. Pat. No. 5,115,184--M. T. Arthur and F. H. Miner, which describe unitary, i.e. one piece roof construction. In some instances, roof sectors are fabricated separately and then joined to provide a final unitary roof Such roofs have been very effective with electric arc steel melting furnaces and other applications.
It has become important to provide spray cooling for submerged arc metallurgical furnaces in which an electrode penetrates a furnace charge containing e.g. metal bearing ore. The arc from the electrode submerged in the furnace charge produces the high temperatures required for reduction of the metal bearing ore, e.g. titanium bearing ore. The thermal conditions to which the furnace roof is exposed in a submerged arc furnace varies considerably from location to location which tends to make the design of a unitary spray cooled roof complex. Also, the roof for a submerged arc furnace tends to be larger in diameter than roofs for steel scrap melting furnaces. The present invention is directed to the particular requirements of a submerged arc metallurgical furnace.